Recently, organic electroluminescent devices have been attracting attentions for use as a flat surface light source. In the organic electroluminescent device, an organic thin film is provided between two electrodes. By applying a voltage on the organic thin film to inject electrons and holes so that they may be recombined, excitons are produced. When the excitons are radiatively deactivated, light is emitted and utilized.
Due to their features such as thinness, light weight, and surface emission, the organic electroluminescent devices are expected to find applications that have not been able to be realized with the conventional lighting apparatuses and light sources.